1. Field of the Invention
The present invention relates to a liquid crystal display device.
2. Description of the Related Art
Light emitting diodes (LEDs) have become widely used as light sources of a backlight unit. For example, there is known an edge light type backlight unit in which, instead of cold-cathode tubes, light emitting diodes are disposed on an end surface of a light guide plate so as to enable surface emission by the light guide plate. Further, there is known an example using light emitting diodes in a direct type backlight unit (Japanese Patent Application Laid-open No. 2009-87879).
In a conventional direct type or edge type backlight unit, the light emitting diodes are generally arranged evenly or at equal intervals. With this arrangement, heat generated from the light emitting diodes is uniform inside the backlight unit.
However, in recent years, even in the direct type backlight unit, there has been a demand that the light emitting diodes be disposed on a substrate which is much smaller in size compared with a liquid crystal panel. In such a case, the light emitting diodes are arranged at unequal pitches in some cases in view of the luminous efficiency. In such a case, heat generation inevitably increases at a portion where the light emitting diodes are provided close to one another. Therefore, some countermeasure against heat is required.